Low Solids Non Dispersed Mud
These mud systems are used both onshore and offshore to drill the 12.1/4in hole. This type of mud is run without the use of thinners, provided the solids content (less gravity solids) of the mud is kept within the desired range.
They tend to be run with inverted rheology where the YP is greater than the PV. The polymer aids the lifting capacity and improves the filter cake characteristics.